House Majority Leader Eric Cantor on Thursday said it appears increasingly likely that Republicans will join anti-war Democrats Friday in demanding an end to U.S. involvement in the civil war in Libya.

The House is expected to take up a resolution by Rep. Dennis Kucinich (D-Ohio) calling for an end to the U.S. operations in the NATO-led campaign in Libya.

House Republicans are set to meet Thursday afternoon to discuss Libya and whether they should back Kucinich. Cantor said GOP support is clearly driven by the lack of a clear mission and the “seeming disregard of the role that Congress plays under the Constitution. I think that’s very real for our Members.”

In an interview with Roll Call on Thursday morning, the Virginia Republican said support for the resolution “could go either way” and that he bluntly warned President Barack Obama of the situation Wednesday morning during a meeting on the debt limit.

“I told the president, ‘you have a real problem with our members in Libya.’ I told him ‘the Kucinich resolution is coming up and frankly I wouldn’t be surprised if it passes, because people are upset,’” Cantor said.

According to a GOP leadership aide, Cantor also called Deputy National Security Adviser Denis McDonough on Wednesday afternoon and reiterated his warning — but so far, the White House has done nothing to respond to Cantor’s concerns.

“The administration, I believe, dropped the ball,” Cantor added, explaining that two main factors have led to GOP unhappiness with the situation in Libya.

“Here’s my take. There was never explained a real reason or mission for our involvement in Libya. And in fact, the official proclamation if you can call it that, by the president, was this is a humanitarian mission. Well, where in the constitution does it say you can commit armed forces for that purpose?”

President Barack Obama decided in March to join a NATO-led mission in Libya that was initially designed to protect civilians and protesters from attacks by Libyan dictator Moammar Gadhafi. That has included U.S. airstrikes on Libyan military and government positions as well as enforcement of a no-fly zone and an arms embargo. The conflict between Gadhafi and protesters, however, has developed into a civil war.

Cantor also pointed to the War Powers Act, which requires the White House to request authority to engage in a military campaign.

“There are deadlines that have been missed, without very clear compliance, lets say that,” Cantor said, adding that while the White House has claimed a letter from Obama to Sen. John McCain (R-Ariz.) fulfilled the law’s requirements.

“I think there’s differences of opinion over that. But the Members certainly don’t feel by and large that that was compliant with seeking authorization on the part of the president for congress’ approval,” Cantor said.

Under the War Powers Act, the president is generally supposed to end military force within 60 days unless lawmakers authorize further action. Obama did not send Congressional leaders a letter requesting their support for the operation until the day of deadline.

Although Cantor did not explicitly accuse the administration of violating the law, his comments were significantly different from those of Speaker John Boehner (Ohio), who when asked Wednesday if Obama had violated the law said, “Technically, no. … Legally, they’ve met the requirements of the War Powers Act.”

Cantor acknowledged that GOP support for Kucinich’s resolution is a politically jarring prospect.

He noted, “It’s counterintuitive to think that we would support Dennis Kucinich. I mean, here’s a guy who’s anti-war, anti-military, and we’re going to support him?”

Meanwhile, on Thursday Boehner said it is incumbent on the White House to make a better case for the administration’s foreign policy goals when it comes to the war efforts not only in Libya, but also in Iraq and Afghanistan.

“Members are a bit weary about the amount of money we’ve spent in Iraq, in Afghanistan and that we’re spending in Libya, and as a result really are wondering what our vital national security interests are there,” Boehner said.

“I think I have a pretty good feel for it, but I really do believe the president really needs to speak out in terms of our mission in Iraq, our mission in Afghanistan, our mission in Libya, and our doubts that our members have are reflecting what they’re hearing from their constituents,” he added.

“The president really does need to step up and help the American people understand why these missions are vital to the national security interests of our country.”